Preheat oven to 180°C. Grease and line a 23cm spring-form cake tin with baking paper.

In a large bowl, sift together flour, cocoa powder, baking soda and salt; set aside. Use an electric mixer with a whisk attachment to whisk together oil, buttermilk, sugar, eggs, food colouring, vinegar and vanilla.

Gently mix through sifted dry ingredients until well incorporated. Do not overmix as this develops gluten, which leads to a tough cake. Spoon mixture into prepared tin. Bake for 50-60 minutes, or until a skewer inserted into the middle of the cake comes out clean. Leave to cool in the tin for 10 minutes, before turning out onto a wire rack to cool completely.

To make vanilla frosting, in a medium saucepan whisk flour and milk together until smooth. Place over medium heat and continue to whisk until milk and flour thickens to a paste-like consistency. Let it cool, stirring occasionally.

Add sugar, vanilla and salt and transfer to the bowl of an electric mixer fitted with a paddle attachment. Beat in the butter, a little at a time until it is fully incorporated.

The mixture will look split but keep beating on high until the icing becomes homogenous.

To assemble, using a serrated knife, slice the cake into three even layers. Spread the bottom two layers with raspberry jam and vanilla frosting.

Top with the last layer and ice with the remaining frosting, covering the sides as well. Cover with a dusting of red velvet cake crumbs, if using.

Smart Tip + The cake base can be made 2-3 days in advance and stored in an airtight container or frozen for up to 1 month. Defrost before using. The vanilla frosting will keep in the fridge for up to one week.